Light double-gluon hybrid states from QCD sum rules

We study the double-gluon hybrid states with the quark-gluon contents $\bar q q gg$ ($q=u/d$) and $\bar s s gg$. We construct twelve double-gluon hybrid currents with various quantum numbers, five of which are found to be zero due to some internal symmetries between the two gluon fields. We use the rest seven currents to perform QCD sum rule analyses. Especially, the masses of the double-gluon hybrid states with the exotic quantum number $J^{PC} = 2^{+-}$ are calculated to be $M_{|\bar q q gg;2^{+-}\rangle} = 2.26^{+0.20}_{-0.25}$ GeV and $M_{|\bar s s gg;2^{+-}\rangle} = 2.38^{+0.19}_{-0.25}$ GeV. Their two- and three-meson decay patterns are also investigated.